A printed circuit board includes at least a wiring layer, a shielding layer and a dielectric layer, wherein the wiring layer includes signal wires and BGA (Ball Grid Array) region and non-BGA region. A plenty of known differential wiring methods for PCBs tend to generally control the wiring width within the non-BGA region in a reasonable range as possibly, of which the wire width/distance is larger; the distance of the pin array in the BGA region is instead smaller, wherein designers generally use the same wire width as the difference pair in the non-BGA region, and reduce the distance between the difference pair in the BGA region, interconnecting with the non-BGA region. However, in fact this design is difficult to ensure the impedance consistency between the BGA region and the non-BGA region, resulting in impedance fluctuation and affecting the signal transmission quality. Specially with the booming development of 4G and 5G high-speed communication networks, requirements for link impedance consistency during high-speed signal transmission are getting higher and higher, which means that for maintaining high quality of high-speed signal transmission the transmission channel impedance must be controlled to keep very stable. The conventional wiring methods of PCBs cannot satisfy the requirements for high-speed signal quality.